Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for North America Nebula: 05-17 (100), 05-18 (100), 05-19 (100), 05-20 (100), 05-21 (100) — by astronomy; check the weather when the night is within four days.

2037-05-04astronomy score per night — click a bar for that night2037-06-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-05-04 Mon	50	—	unknown	01:35–04:25 (good, 2.83 h)	87.2° 07:30	6.17	72%	68.9°
2037-05-05 Tue	61	—	unknown	01:10–04:25 (good, 3.25 h)	87.2° 07:25	6.11	62%	64.9°
2037-05-06 Wed	69	—	unknown	01:05–04:20 (good, 3.25 h)	87.2° 07:20	6.06	53%	62.0°
2037-05-07 Thu	76	—	unknown	01:00–04:20 (good, 3.33 h)	87.2° 07:15	6.0	43%	60.5°
2037-05-08 Fri	84	—	unknown	00:55–04:20 (good, 3.42 h)	87.2° 07:10	5.94	34%	60.4°
2037-05-09 Sat	89	—	unknown	00:55–04:15 (good, 3.33 h)	87.2° 07:10	5.89	25%	61.7°
2037-05-10 Sun	91	—	unknown	00:50–04:15 (good, 3.42 h)	87.2° 07:05	5.83	18%	64.3°
2037-05-11 Mon	93	—	unknown	00:45–04:15 (good, 3.5 h)	87.2° 07:00	5.78	11%	68.0°
2037-05-12 Tue	94	—	unknown	00:40–04:10 (good, 3.5 h)	87.2° 06:55	5.72	6%	72.6°
2037-05-13 Wed	96	—	unknown	00:35–04:10 (good, 3.58 h)	87.2° 06:50	5.67	2%	78.1°
2037-05-14 Thu	97	—	unknown	00:35–04:10 (good, 3.58 h)	87.2° 06:50	5.61	0%	84.1°
2037-05-15 Fri	97	—	unknown	00:30–04:05 (good, 3.58 h)	87.2° 06:45	5.56	1%	90.4°
2037-05-16 Sat	99	—	unknown	00:25–04:05 (good, 3.67 h)	87.2° 06:40	5.51	3%	96.9°
2037-05-17 Sun	100	—	unknown	00:20–04:05 (good, 3.75 h)	87.2° 06:35	5.46	8%	103.2°
2037-05-18 Mon	100	—	unknown	00:15–04:00 (good, 3.75 h)	87.2° 06:35	5.4	15%	108.9°
2037-05-19 Tue	100	—	unknown	00:15–04:00 (good, 3.75 h)	87.2° 06:30	5.35	24%	113.8°
2037-05-20 Wed	100	—	unknown	00:15–04:00 (good, 3.75 h)	87.2° 06:25	5.3	34%	117.4°
2037-05-21 Thu	100	—	unknown	00:10–04:00 (good, 3.83 h)	87.2° 06:20	5.25	45%	119.3°
2037-05-22 Fri	100	—	unknown	00:10–03:55 (good, 3.75 h)	87.2° 06:15	5.21	56%	119.3°
2037-05-23 Sat	100	—	unknown	00:10–03:55 (good, 3.75 h)	87.2° 06:15	5.16	68%	117.4°
2037-05-24 Sun	98	—	unknown	00:10–03:55 (good, 3.75 h)	87.2° 06:10	5.11	78%	113.7°
2037-05-25 Mon	83	—	unknown	00:10–03:50 (good, 3.67 h)	87.2° 06:05	5.07	87%	108.6°
2037-05-26 Tue	75	—	unknown	00:15–03:50 (good, 3.58 h)	87.2° 06:00	5.02	93%	102.5°
2037-05-27 Wed	68	—	unknown	00:20–03:50 (good, 3.5 h)	87.2° 05:55	4.98	98%	95.8°
2037-05-28 Thu	61	—	unknown	00:50–03:50 (good, 3.0 h)	87.2° 05:55	4.94	100%	89.0°
2037-05-29 Fri	56	—	unknown	01:10–03:50 (good, 2.67 h)	87.2° 05:50	4.9	99%	82.4°
2037-05-30 Sat	53	—	unknown	01:10–03:45 (good, 2.58 h)	87.2° 05:45	4.86	96%	76.2°
2037-05-31 Sun	54	—	unknown	00:35–03:45 (good, 3.17 h)	87.2° 05:40	4.82	92%	70.8°
2037-06-01 Mon	70	—	unknown	23:20–03:45 (good, 4.42 h)	87.2° 05:35	4.78	85%	66.4°
2037-06-02 Tue	80	—	unknown	23:20–03:45 (good, 4.42 h)	87.2° 05:35	4.75	77%	63.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-05-04&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.